The invention relates to an apparatus for testing an automatic electronic flash, and more particularly, to such testing apparatus which is used for a combination of a single lens reflex camera of the TTL direct photometry type and a TTL automatic electronic flash.
As is recognized, a single lens reflex camera of the TTL direct photometry type is adapted to receive reflected light from an object being photographed which passes through a taking lens. The reflected light is then reflected by a shutter blind surface and a film surface so as to impinge on a photometric element contained in an exposure control circuit for purpose of exposure control. A TTL automatic electronic flash is adapted to cooperate with such single lens reflex camera, and includes an illumination control circuit which is activated by an output from the exposure control circuit within the camera whenever the flash is combined with the camera, thus allowing the light emission from a flash discharge tube to be controlled.
In such a flash-and-camera combination, the light emission from the electronic flash occurs in interlocked relationship with a shutter release operation. Specifically, as a first shutter blind begins to run, an integrating circuit which forms part of the exposure control circuit is activated to derive an integrated output. The flash discharge tube begins to emit light at the termination of the running of the first shutter blind, and when the integrated output reaches an optimum value, the illumination control circuit is activated to interrupt the light emission from the tube (see FIG. 1).
At times, it is desired to test the automatic electronic flash to determine whether it operates properly. With the conventional combination, the light emission circuit and the illumination control circuit of the electronic flash cannot be activated unless the shutter of the camera is actually operated. Consequently, it follows that the shutter must be operated to permit an exposure of the film disadvantageously when it is desired to test the electronic flash.